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TELESCOPE OPERATIONS

DIGITAL-ELECTRO-MECHANICAL REFERENCE INFORMATION

Info

Information sources include Comsat/LM documentation, GBT Memos, and information from Green Bank staff personnel.

The Penn Array is also known as the Mustang receiver.

Electronics

Receiver Turret Locations

GBT Gregorian Receiver Locations on the Turret
Turret Position Turret Angle (Deg.) Receiver or Instrument Receiver band
N1 359.68 1_2 (1.15-1.73 GHz) L
N2 299.65 4_6 (3.95-5.85 GHz) C / Penn Array (when installed)
N3 259.65 40_50 (40.0-50.0GHz) Q
N4 219.66 8_10 (8-10.1 GHz) X
N5 179.65 2_3 (1.73-2.60 GHz) S
N6 139.64 18_26 (18-26.5 GHz) K
N7 99.648 26_40 (26.0-40.0 GHz) Ka
N8 59.66 12_18 (12-15.4 GHz) / Zpectrometer Ku / Zpect (when installed)

Receiver Circular Polarization Optimization

S-Band
Sky Frequency (MHz) Gain X Setting Gain Y Setting
< 1900 0 +2.5
1953 0 +2.0
2006 0 +1.0
2165 0 ±0.0
2218 0 -1.0
2324 0 -3.0
2370 0 -4.74
2380 0 -5.11
2430 0 -7.0
> 2483 +3.0 -2.0

L-Band
Sky Frequency (MHz) Low Cal High Cal Gain X Setting Gain Y Setting Phase
1300 2.1 28.0 4.6 ±0.0 56.0
1400 2.1 28.2 4.6 ±0.0 52.0
1500 2.1 28.2 4.6 ±0.0 50.0
1600 2.2 31.4 4.6 ±0.0 46.0

Cryogenics

Compressors Supplying Receivers
Compressor #1 Compressor #2 Compressor #3 Compressor #4 Compressor #5 Compressor #6
Prime Focus 1 Q-Band Penn Array (when installed S-Band K-Band Ku-Band
Prime Focus 2 none C-Band X-Band Ka-Band L-Band

Telescope Limits

Azimuth Limits (CW) Deg.
Software Pre Limit Redundant Pre Limit Final Limit Redundant Final Limit Cleo Indicated Position
90.200 90.674 91.220 91.628 92.200 450

Azimuth Limits (CCW) Deg.
Software Pre Limit Redundant Pre Limit Final Limit Redundant Final Limit Cleo Indicated Position
270.200 269.729 269.200 268.564 268.200 -90

Elevation Limits (Up) Deg.
Software Pre Limit Redundant Pre Limit Final Limit Redundant Final Limit
95.100 95.355 95.593 95.854 96.084

Elevation Limits (Down) Deg.
Software Pre Limit Redundant Pre Limit Final Limit Redundant Final Limit
4.900 4.663 4.411 4.155 3.919

Subreflector Actuator Software Limits
Actuator Retracted Limit (inches) Extended Limit (inches)
Y1 98.64 135.69
Y2 97.88 136.57
Y3 97.88 136.57
X1 114.24 144.85
X2 114.24 144.85
Z1 56.70 76.11

Telescope Movement Rates (Azimuth - Elevation)

Azimuth (Full Slew) Elevation (Full Slew)
Degrees/Min Arc Minutes/Min Degrees/Min Arc Minutes/Min
36 2160 18 1072

Degree/Min to Arc Minutes/Min Conversion Table
Deg/Min Arc Min/Min   Deg/Min Arc Min/Min   Deg/Min Arc Min/Min   Deg/Min Arc Min/Min
1 60   11 660   21 1260   31 1860
2 120   12 720   22 1320   32 1920
3 180   13 780   23 1380   33 1980
4 240   14 840   24 1440   34 2040
5 300   15 900   25 1500   35 2100
6 360   16 960   26 1560   36 2160
7 420   17 1020   27 1620   37 2220
8 480   18 1080   28 1680   38 2280
9 540   19 1140   29 1740   39 2340
10 600   20 1200   30 1800   40 2400

Conversion Formulae

Degrees Per Minute to Arc Minutes Per Minute: Deg/Min x 60 Arc Min/Deg' = Arc Min/Min

Arc Minutes Per Minute to Degrees Per Minute: Arc Min/Min ÷ 60 = Degrees Per Minute

Unusual Observing Operations

Prime Focus Pointing Coefficients - Focus Tracking Off (Arcmins) Assumes axial focus (Y = 900mm) and lateral focus (X = 500mm)

-- DavidRose - 6 Feb 2008

Topic Digital-Electro-MechanicalReferenceInformation . { Edit | Attach | Ref-By | Printable | Diffs | r1.8 | > | r1.7 | > | r1.6 | More }
Revision r1.8 - 06 Feb 2008 - 20:55 GMT - DavidRose
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